1. Field of the Invention
This invention relates to improvements in ink jet recording heads. More particularly, the present invention provides an ink jet recording head capable of handling higher resolutions by providing a manufacturing method involving no deterioration in production yield even when using pressure chamber plates that are thinner than conventionally.
2. Description of the Related Art
Ink jet recording heads according to the prior art comprise a pressure chamber plate, a nozzle plate bonded to one side of the pressure chamber plate, and a vibrating plate provided on the other side of the pressure chamber plate.
The pressure chamber plate is configured by forming multiple ink-holding pressure chambers on a silicon wafer, and bonding thereto a nozzle plate having nozzle holes arranged thereon corresponding to the pressure chambers (cavities). On the side of the vibrating plate opposite the pressure chambers are formed piezoelectric elements. Given this configuration, when the pressure chambers are filled with ink and a voltage is applied to the piezoelectric elements, changes are produced in the volume of the piezoelectric material, and hence changes are produced in the volumes of the pressure chambers. These changes in pressure cause ink to be discharged from the nozzle holes. In the prior art, the thickness of the silicon wafer and the height of the pressure chambers are made roughly the same.
Demand has grown in recent years, however, for higher resolution in ink jet recording heads. In order to enhance the resolution of the ink jet recording head, it is necessary to reduce both the width and height of the pressure chambers and the width of the partitioning side walls between the pressure chambers.
However, the thickness of the silicon wafers that can be used currently is on the order of 200μ, which poses a limit on the height of the side walls partitioning the pressure chambers. When the thickness of the silicon wafer is made thinner than this, the mechanical strength of the silicon wafer cannot be preserved, leading to damage to the silicon wafer during the process of forming the pressure chambers and making handling otherwise problematic.
One conceivable solution is to form thinner pressure chamber plates separately from the piezoelectric elements, use a different base plate for forming the piezoelectric elements, and finally bond the pressure chamber plate and the piezoelectric elements together. When this is done, it is no longer necessary to send the pressure chamber plate through multiple process steps in order to form the piezoelectric elements, and the drawbacks of employing a thin pressure chamber plate can be eliminated.
However, because the height of the piezoelectric elements is no more than a few μ, it is very difficult to peel the piezoelectric elements away from the base plate after they are formed without affecting them.